Tag Archives: Mammals

Kirjauutuus: Jääkauden jälkeläiset

Pirkko Ukkonen ja Kristiina Mannermaa
JÄÄKAUDEN JÄLKELÄISET
Suomen lintujen ja nisäkkäiden varhainen historia

Museovirasto 2017, 240 s.

“Museoviraston uunituore Jääkauden jälkeläiset -julkaisu on kertomus Suomessa jääkauden aikana eläneistä eläimistä, niiden väistymisestä ilmaston muuttuessa ja nykyisten lintu- ja nisäkäslajien saapumisesta maahan sen vapautuessa lopullisesti jäästä ja jäätikön sulavesistä. Yleistajuinen kirja on suunnattu kaikille muinaisuudesta kiinnostuneille lukijoille, mutta se toimii myös tietolähteenä, oppikirjana ja hakuteoksena tutkijoille, opettajille, opiskelijoille ja medialle.”

Lehdistötiedote

Club meeting 13.12. Prof. Zhang Zhaoqun

Hello All,

next week we will have a meeting with a special guest presentation. Our guest will be Prof. Zhang Zhaoqun from Key Laboratory of Vertebrate Paleontology and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology. He will present us a talk titled “Hunting for Oligocene mammals in Inner Mongolia”. I hope many of you can attend, glögg will also be served!

See you on Tuesday 13.12. at 16.00 in C108, Physicum!

 

Geoscience seminar 22.4. – Prof. Mikael Fortelius

Dear All,

The Geoscience seminar this week (Friday 22nd) will be given by professor Mikael Fortelius. Mikael will talk about his recent research from Turkana Basin (abstract below).

Friday 22.4.

Time: 14.15

Location: D114, Physicum, Kumpula Campus

Title: AN ECOMETRIC ANALYSIS OF THE FOSSIL MAMMAL RECORD OF THE TURKANA BASIN

All are most welcome!

***

Abstract

Although ecometric methods have been used to analyse fossil mammal faunas and environments of Eurasia and North America, such methods have not yet been applied to the rich fossil mammal record of East Africa. Here we report results from analysis of a combined dataset spanning east and west Turkana from Kenya between 7 and 1 million years ago. We provide temporally and spatially resolved estimates of temperature and precipitation and discuss their relationship to patterns of faunal change and propose a new hypothesis to explain the lack of a temperature trend. We suggest that the regionally arid Turkana Basin may between 4 and 2 million years ago have acted as a ‘Species Factory’, generating ecological adaptations in advance of the global trend. We show a persistent difference between the eastern and western sides of the Turkana Basin and suggest that the wetlands of the shallow eastern side could have provided additional humidity to the terrestrial ecosystems. Pending further research, a transient episode of faunal change centred at the time of the KBS member (1.87-1.53 million years ago) may be equally plausibly attributed to climate change or to a top-down ecological cascade initiated by the entry of technologically sophisticated humans.

 

Mammalian skull heterochrony

Cool paper by Marcelo Sanchez-Villagra and colleagues.

Mammalian skull heterochrony reveals modular evolution and a link between cranial development and brain size

The multiple skeletal components of the skull originate asynchronously and their developmental schedule varies across amniotes. Here we present the embryonic ossification sequence of 134 species, covering all major groups of mammals and their close relatives. This comprehensive data set allows reconstruction of the heterochronic and modular evolution of the skull and the condition of the last common ancestor of mammals. We show that the mode of ossification (dermal or endochondral) unites bones into integrated evolutionary modules of heterochronic changes and imposes evolutionary constraints on cranial heterochrony. However, some skull-roof bones, such as the supraoccipital, exhibit evolutionary degrees of freedom in these constraints. Ossification timing of the neurocranium was considerably accelerated during the origin of mammals. Furthermore, association between developmental timing of the supraoccipital and brain size was identified among amniotes. We argue that cranial heterochrony in mammals has occurred in concert with encephalization but within a conserved modular organization.
– Jacqueline

Mammal disparity decreases during the Cretaceous angiosperm radiation

Latest by Polly…

Abstract

Fossil discoveries over the past 30 years have radically transformed traditional views of Mesozoic mammal evolution. In addition, recent research provides a more detailed account of the Cretaceous diversification of flowering plants. Here, we examine patterns of morphological disparity and functional morphology associated with diet in early mammals. Two analyses were performed: (i) an examination of diversity based on functional dental type rather than higher-level taxonomy, and (ii) a morphometric analysis of jaws, which made use of modern analogues, to assess changes in mammalian morphological and dietary disparity. Results demonstrate a decline in diversity of molar types during the mid-Cretaceous as abundances of triconodonts, symmetrodonts, docodonts and eupantotherians diminished. Multituberculates experience a turnover in functional molar types during the mid-Cretaceous and a shift towards plant-dominated diets during the late Late Cretaceous. Although therians undergo a taxonomic expansion coinciding with the angiosperm radiation, they display small body sizes and a low level of morphological disparity, suggesting an evolutionary shift favouring small insectivores. It is concluded that during the mid-Cretaceous, the period of rapid angiosperm radiation, mammals experienced both a decrease in morphological disparity and a functional shift in dietary morphology that were probably related to changing ecosystems.

http://rspb.royalsocietypublishing.org/content/280/1771/20132110.abstract

Oligo-Miocene climate change and mammal body-size evolution: a test of Bergmann’s Rule

Oligo-Miocene climate change and mammal body-size evolution in the northwest United States: a test of Bergmann’s Rule

John D. Orcutt and Samantha S. B. Hopkins

Paleobiology: Fall 2013, Vol. 39, No. 4, pp. 648-661.

Whether or not climate plays a causal role in mammal body-size evolution is one of the longest-standing debates in ecology. Bergmann’s Rule, the longest-standing modeladdressing this topic, posits that geographic body-mass patterns are driven by temperature, whereas subsequent research has suggested that other ecological variables, particularly precipitation and seasonality, may be the major drivers of body-size evolution. While paleoecological data provide a unique and crucial perspective on this debate, paleontological tests of Bergmann’s rule and its corollaries have been scarce. We present a study of body-size evolution in three ecologically distinct families of mammal (equids, canids, and sciurids) during the Oligo-Miocene of the northwest United States, an ideal natural laboratory for such studies because of its rich fossil and paleoclimatic records. Body-size trends are different in all three groups, and in no case is a significant relationship observed between body size and any climatic variable, counter to what has been observed in modern ecosystems. We suggest that for most of the Cenozoic, at least in the Northwest, body mass has not been driven by any one climatic factor but instead has been the product of complex interactions between organisms and their environments, though the nature of these interactions varies from taxon to taxon. The relationship that exists between climate and body size in many groups of modern mammals, therefore, is the exception to the rule and may be the product of an exceptionally cool and volatile global climate. As anthropogenic global warming continues and ushers in climatic conditions more comparable to earlier intervals of the Cenozoic than to the modern day, models of corresponding biotic variables such as body size may lose predictive power if they do not incorporate paleoecological data.

http://www.psjournals.org/doi/abs/10.1666/13006

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Laura

Course on Mammalian diet evolution 23.9-3.12.2013

Welcome to a course on diet evolution in mammals.

– starts on Tuesday 23.9 12-14.00 in C108 (quota 15 students),

– maximum credits obtainable – 4: 2 credits for exam, 1 credit for essay, 1 cr for presence. Evaluation is based on the exam and/or the essay.

The course will describe the evolution of mammalian diets from early mammals to modern humans, adaptation of their teeth and digestive tracts to environment, and methods studying mammalian diet.

Several lectures will be focused on primate diets (monkeys, apes and early humans), dietary adaptations of early hominines (plant versus meat eaters) and the dietary changes in modern humans.

The first lectures will give an introduction to mammals, their teeth and digestive systems and their adaptation to environment (skull and teeth demonstration of the main features and basic differences among mammals).

 

Preliminary outline of lectures:

24.9 Lecture 1. Introduction to mammals, osteology

01.10 Lecture 2. Introduction to teeth, origin and morphology

08.10 Lecture 3. Demonstration, skulls, teeth

15.10 Lecture 4. Methods: teeth as proxy to environment: morphology (hypsodonty, crown type), structure (mesowear, microwear, GISWear), chemistry (isotope analysis)

29.10 Lecture 5. Diet and digestive system in mammals

05.11 Lecture 6. Early mammal diets, carnivory and carnivores

12.11 Lecture 7. Evolution of herbivory and herbivores, omnivory

19.11 Lecture 8. Primate diets, monkey, apes, early hominines

26.11 Lecture 9. Early humans’ changing environments, change in human diets over time

03.12 Lecture 10. Human subsistence and evolutionary nutrition (fossil versus modern)

 

— Diana